There are three main categories which describe the invasiveness of medical procedures. These are: non-invasive procedures, minimally invasive procedures, and invasive procedures. A medical procedure is strictly defined as non-invasive when no break in the skin is created and there is no contact with the mucosa, or skin break, or internal body cavity beyond a natural or artificial body orifice.
A category of non-invasive diagnostic techniques involves diagnosis via diagnostic imaging techniques. Such imaging techniques may include ultrasonography, dermatoscopy, magnetic resonance imaging (MRI) etc.
Non-invasive procedures have the benefit that they may cause no or minimal pain to the patient, no scarring, recovery is immediate, and the incidence of post-surgical complications, such as adhesions may be avoided. However, for a number of diseases, the diagnostic accuracy of non-invasive techniques may be questionable. In such cases, minimally invasive techniques may be used so medical technology has developed minimally-invasive methods, such as hypodermic injection (using the syringe), endoscopy, percutaneous surgery, laparoscopic surgery, coronary catheterization, angioplasty, stereotactic surgery, amniocentesis and many others.
Although minimally-invasive methods are considered safe and accurate for a number of diagnoses, a large number of patients may be reluctant to have them performed on their body for a number of reasons, discomfort being the most common one.
For the above reasons, it would be desirable to have a non-invasive imaging technique that may diagnose a disease with the same accuracy as a minimally invasive technique.